Additives for fuels and lubricants

ABSTRACT

An additive compound comprising a derivative of particular fatty acids and polyamines has been found to be friction reducing, and particularly readily miscible in fuels and lubricants. The fatty acid has more than 12 carbon atoms and at least one carboxylic group. The polyamine residue has more than two nitrogen atoms. The mole ratio of the carboxylic groups to nitrogen atoms used to form the compound is greater than 0.8 carboxylic groups per 1 nitrogen atom.

The present invention relates to additives for fuels and lubricants, to improvements in stability of additives in fuels and lubricants, and to improvements in the operation of internal combustion engines.

Over the years the price of fuel has undergone fluctuations, but the trend has been for it to become more expensive. This is to be expected fundamentally because of limitations in the supply, but also because of the taxation policy of Governments. The trend is expected to continue.

The present invention is concerned with additives which enable internal combustion engines to use fuel more efficiently; that is, with additives which increase the useful energy derived from an internal combustion engine and reduce the non-useful, or “lost”, energy.

There is a vast body of published information, patents and literature, concerning fuels and lubricants, and friction reducing additives for lubricants and for fuels. However there is no causal relationship between the addition of an additive to a fuel or lubricant, and the achievement of higher efficiency or greater useful output. For example a lubricating additive for a fuel may be added in order to achieve lubrication, and hence maintain good operation, of a fuel pump, and not be directly associated with improvement in useful output.

A very widely used test to assess the lubricity of a fuel is the HFRR test. In the HFRR a wear scar is produced by a ball moved in reciprocation over the surface of an object, both immersed in a sample fuel. The size of the wear scar is taken as a measure of lubricity, and the test is very apt for situations in which one surface bears under load on another, and the aim is to assess wear.

The sliding of a plurality of pistons within their corresponding cylinders gives rise to a substantial energy loss when operating an engine.

Another test is the TE77 reciprocating sliding wear test. From measurements taken using a high frequency reciprocating tribometer, the percentage change in Coefficient of Friction (μ) due to the presence of a friction modifier additive can be calculated.

In an article entitled “Simulated fuel dilution and friction-modifier effects on piston ring friction” by 0. Smith et al, published in Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology, Mechanical Engineering Publications, vol. 220, no. 3, pp. 181-189, published on 1 Jan. 2006, the authors describe how 40-60% of mechanical friction can be attributed to the piston/ring/cylinder wall interface. The authors go on to describe how much of this is a result of the compression ring whose lubrication is kept purposely minimal to control exhaust emissions. A series of tests using a TE-77 reciprocating tribometer was used to investigate the friction coefficient reduction effects of fatty acids on a base oil. Implicit in this teaching is the idea that the fuel and the lubricant are not isolated from one another; there is a feed of fuel into the lubricant, particularly in the cylinder liner oil film. The authors postulate that the fuel may be used to administer friction modifier additives directly to the top ring zone of the engine where its effects are most beneficial.

It is an object of the present invention primarily to achieve improved performance of friction reducing additives in fuels and/or lubricants.

It is a further object of the present invention to provide friction reducing additives which have excellent compatibility (including miscibility) in fuels and/or lubricants.

In accordance with a first aspect of the present invention there is provided a method of reducing friction in an engine, by use of an additive compound present in the fuel and/or lubricant which is employed, the additive compound comprising:

(1) a fatty acid residue having more than 12 carbon atoms and at least one carboxylic group; and (2) a polyamine residue having more than two nitrogen atoms; wherein the mole ratio of the carboxylic groups to nitrogen atoms used to form the compound is greater than 0.8 carboxylic groups per 1 nitrogen atom.

In accordance with the method we have found that certain additives gave excellent results in reducing friction, as revealed by slide tests which reflected the sliding action of a piston within a cylinder. We found also that a sub-group of such additives also had particularly high levels of compatibility (which may be expressed as stability and/or miscibility) in fuels or lubricants. As noted in the 0. Smith et al article referenced above, even when additives are dosed into fuels there is likely to be carry over into the lubricant region of an engine, particularly in the upper cylinder area. This may be regarded as something the lubricant must be able to cope with, without instability or immiscibility arising; or it may be regarded as something the formulator may exploit; for example by using the fuel to deliver a friction-reducing additive which may act locally, for example in the cylinder liner oil film, or elsewhere in the lubricant in the cylinders, or in the bulk lubricant; or in more than one such location. Any such approach represents a preferred feature of the present invention.

The improvement may be as defined in the second aspect, below.

The improvement may be as defined in the third aspect, below.

The improvement may be as defined in the fourth aspect, below.

In accordance with a second aspect of the present invention there is provided the use of an additive compound in a fuel and/or lubricant for the purpose of increasing the efficiency of an engine utilising said fuel and/or lubricant, wherein the additive compound comprises:

(1) a fatty acid residue having more than 12 carbon atoms and at least one carboxylic group; and (2) a polyamine residue having more than two nitrogen atoms; wherein the mole ratio of the carboxylic groups to nitrogen atoms used to form the compound is greater than 0.8 carboxylic groups per 1 nitrogen atoms.

In accordance with a third aspect of the present invention there is provided the use of an additive compound in a fuel and/or lubricant for the purpose of reducing friction in an engine utilising said fuel and/or lubricant, wherein the additive compound comprises:

(1) a fatty acid residue having more than 12 carbon atoms and at least one carboxylic group; and (2) a polyamine residue having more than two nitrogen atoms; wherein the mole ratio of the carboxylic groups to nitrogen atoms used to form the compound is greater than 0.8 carboxylic groups per 1 nitrogen atoms.

In accordance with a fourth aspect of the present invention there is provided the use of an additive compound in a fuel, for the purpose of improving the friction performance of an engine lubricant, wherein the additive compound comprises:

(1) a fatty acid residue having more than 12 carbon atoms and at least one carboxylic group; and (2) a polyamine residue having more than two nitrogen atoms; wherein the mole ratio of the carboxylic groups to nitrogen atoms used to form the compound is greater than 0.8 carboxylic groups per 1 nitrogen atom.

The lubricant may be improved adjacent to the piston rings, where the concentration of the transferred additive may be high; and/or it may be improved by dispersion of said additive into the bulk fuel. In either such case excellent miscibility is required.

Equally, excellent miscibility is required in the fuel in which the additive was delivered, in this aspect.

In accordance with a fifth aspect of the present invention there is provided the use of fatty acid-polyamine derivative in a fuel and/or lubricant for a first purpose of reducing friction in an engine, and for a second purpose of achieving stability of the derivative in the fuel and/or lubricant, wherein the derivative comprises:

(1) a fatty acid residue having more than 12 carbon atoms and at least one carboxylic group; and (2) a polyamine residue having more than two nitrogen atoms; wherein the mole ratio of the carboxylic groups to nitrogen atoms used to form the compound is greater than 0.8 carboxylic groups per 1 nitrogen atom.

The improvement described in the first to fifth aspects may suitably be improvement indicated by HFRR testing, as described herein; for example, for diesel, with reference to standard test method IP 450: “Diesel fuel—Assessment of lubricity using the high-frequency reciprocating rig (HFRR)”, or for gasoline, using the modified HFRR method described in the examples in this specification.

The improvement described in the first to fifth aspects may suitably be improvement indicated by TE77 testing, as described herein.

Reducing friction in an engine in this specification is preferably reducing friction in cylinders of the engine.

The improvement described in the first to fifth aspects may suitably be improvement indicated by testing for compatibility as between the additive compound (i.e. the acid-amine derivative) and the fuel and/or lubricant, as described herein; preferably to assess miscibility therebetween, on mixing at ambient temperature.

The additive compound could be supplied in a solvent, used to deliver the additive compound into a fuel and/or lubricant.

Preferably, in accordance with this invention, an additive compound is added to a fuel and/or lubricant directly or via a said solvent. The additive compound may be added into a lubricant by direct addition thereto or from a fuel, by passing piston rings, in use. Thus, compatibility in all such liquids is sought.

The following statements of preferred features of the present invention apply to any of the first, second, third, fourth and fifth aspects, and to the fifth, sixth, seventh, eighth and ninth aspects set forth later.

A derivative of a fatty acid and a polyamine useful in the present invention may be a fatty acid amide. Some unreacted fatty acid and/or unreacted polyamine may be present, though it is preferred that at least one of the acid and nitrogen functions undergo substantially complete reaction; and preferably both do, when they are present as molar equivalents (by functional groups).

A derivative of a fatty acid and a polyamine useful in the present invention may be a salt of a fatty acid and a polyamine. Some unreacted fatty acid and/or unreacted polyamine may be present, though it is preferred that both the acid and nitrogen functions undergo substantially complete reaction; and preferably both do, when they are present as molar equivalents (by functional groups).

A derivative used in the present invention may comprise a fatty acid amide and a salt of a fatty acid and a polyamine. This may be produced by admixture but is preferably produced by a reaction between a fatty acid and a polyamine, which yields a mixed reaction product. Some unreacted fatty acid and/or unreacted polyamine may be present, though it is preferred that both the acid and nitrogen functions undergo substantially completely reaction; and preferably both do, when they are present as molar equivalents (by functional groups).

In this specification when we talk about the amount or ratio of this additive we mean, when there is more than one of the said compounds, the summated amount. In particular, carboxylic acids, such as TOFA, are usually blends of homologous compounds.

In this specification when we talk about the number of carbon atoms, nitrogen atoms or carboxylic acid groups we are referring, as is conventional, to the mean number of such atoms or groups, per molecule.

In a fatty acid having a stated number of carbon atoms and at least one carboxylic group, the carbon atom(s) present in the carboxylic group(s) are included in that stated number.

Thus, the incorporation of the defined fatty acid-polyamine derivative into fuel can provide wear benefits—for example improving the sliding action of the pistons in their cylinders and thereby improve the fuel economy—whilst providing a high degree of assurance that the additive compound will remain solvated in the fuel; preferably also a high degree of assurance that the additive compound will remain solvated in the solvent (e.g. hydrocarbon) used for an additive composition; and preferably also a high degree of assurance that the additive compound will remain solvated in an engine lubricant hydrocarbon, when passage past the piston rings of an engine occurs.

Preferably the carboxylic groups referred to herein are carboxylic acid groups —COOH before reaction.

Preferably, the fatty acid is represented by the formula:

R(COOH)_(n)

wherein R represents a hydrocarbyl group having at least (13 minus n) carbon atoms, preferably at least (15 minus n) carbon atoms.

Suitably n may be 1, 2, 3 or 4, more preferably 1 or 2.

When n is 1 (one), as is most preferred, R is preferably a hydrocarbyl group having at least 12 carbon atoms, preferably at least 14 carbon atoms.

Preferably R is a hydrocarbyl group having up to 50 carbon atoms, preferably up to 32 carbon atoms, most preferably up to 24 carbon atoms.

R may include aromatic and heterocyclic groups. The preferred hydrocarbyl groups are aliphatic groups such as an alkyl group and an alkenyl group, which may have a straight chain or a branched chain, of suitable length to meet the definition given herein. Examples of preferred fatty acids are aliphatic acids having 12 to 30 carbon atoms, preferably 14 to 30 carbon atoms, and include myristic acid, stearic acid, isostearic acid, arachic acid, behenic acid, lignoceric acid, cerotic acid, montanic acid, melissic acid, palmitic acid, oleic acid, eraidic acid, linolic acid, linoleic acid, fatty acid of coconut oil, fatty acid of hardened fish oil, fatty acid of hardened rapeseed oil, fatty acid of hardened tallow oil, soy fatty acid, and fatty acid of hardened palm oil. The examples further include dodecenyl succinic acid and its anhydride.

Most preferably, the fatty acid is a monocarboxylic acid (n is 1), whose group R has from 12 to 30 carbon atoms; for example oleic acid, isostearic acid, stearic acid or tall oil fatty acid.

Preferred fatty acids are those derived from vegetable oils and animal oils and fats.

In some preferred embodiments, mixtures of fatty acids are preferred; for example mixtures of fatty acids derived from vegetable oils and animal oils and fats.

Preferably nitrogen atoms in the polyamine are present as amine groups, suitably unsubstituted amine groups.

Primary, secondary or tertiary amine groups may be present in the polyamine, as appropriate. Preferably —NH₂ groups are present at the termini of molecules and —NH— groups at intermediate positions of the molecules.

The nitrogen atoms referred to in the definitions and claims of this invention are of groups which can react with the carboxylic groups.

A salt of a fatty acid and a polyamine may be obtained by mixing a said acid and the amine, for example at a temperature of 20 to 100° C.

A fatty acid amide may be prepared by a dehydration-condensation reaction between a said fatty acid and a polyamine, for example at a temperature of 20 to 200° C. under atmospheric or reduced pressure.

Preferred features of a polyamine which can be used for the formation of a salt or an amide are as follows.

Preferably the polyamine is an aliphatic polyamine, suitably having a hydrocarbyl group(s) of 4 to 50 carbon atoms, preferably 4 to 20 carbon atoms.

Preferably the polyamine has 3 to 10 nitrogen atoms, preferably 3 to 6 nitrogen atoms. Especially preferred polyamines include diethylene triamine (DETA), triethylene tetramine (TETA), tetraethylene pentamine (TEPA), and pentaethylene hexamine (PEHA).

Preferably the mole ratio of the carboxylic groups to nitrogen atoms used to form the derivative in the invention is at least 0.9 carboxylic groups per 1 nitrogen atom, more. Preferably at least 0.95 carboxylic groups per 1 nitrogen atom, and most preferably at least 0.98 carboxylic groups per 1 nitrogen atom.

Preferably the mole ratio of the carboxylic groups to nitrogen atoms used to form the derivative in the invention is up to 3 carboxylic groups per 1 nitrogen atom, more preferably up to 2 carboxylic groups per 1 nitrogen atom, and preferably up to 1.5 carboxylic groups per 1 nitrogen atom. More preferably the mole ratio of the carboxylic groups to nitrogen atoms used to form the derivative in the invention is up to 1.2 carboxylic groups per 1 amino group, more preferably up to 1.1 carboxylic groups per 1 amino group, and most preferably at least 1.02 carboxylic groups per 1 nitrogen atom.

One preferred embodiment uses a reaction product of a monocarboxylic acid as defined herein, preferably selected from TOFA, oleic acid and isostearic acid (preferably TOFA) and diethylene triamine, in a molar ratio (expressed as the reactant compounds rather that as reactive groups) of at least 2.5 to 1, preferably at least 2.8 to 1, more preferably at least 2.95 to 1, acid to amine. Suitably the molar ratio (also expressed in such terms) is up to 6 to 1, preferably up to 4 to 1, preferably up to 3.5 to 1, preferably up to 3.2 to 1, more preferably up to 3.05 to 1, acid to amine.

One preferred embodiment uses a reaction product of a monocarboxylic acid as defined herein, preferably selected from TOFA, oleic acid and isostearic acid (preferably TOFA) and triethylene tetramine, in a molar ratio (expressed as the reactant compounds rather that as reactive groups) of at least 3.5 to 1, preferably at least 3.8 to 1, more preferably at least 3.95 to 1, acid to amine. Suitably the molar ratio (also expressed in such terms) is up to 7 to 1, preferably up to 5 to 1, preferably up to 4.5 to 1, preferably up to 4.2 to 1, more preferably up to 4.05 to 1, acid to polyamine compound.

One preferred embodiment uses a reaction product of a monocarboxylic acid as defined herein, preferably selected from TOFA, oleic acid and isostearic acid (preferably TOFA) and tetraethylene pentamine, in a molar ratio (expressed as the reactant compounds rather that as reactive groups) of at least 4.5 to 1, preferably at least 4.8 to 1, more preferably at least 4.95 to 1, acid to amine. Suitably the molar ratio (also expressed in such terms) is up to 8 to 1, preferably up to 6 to 1, preferably up to 5.5 to 1, preferably up to 5.2 to 1, more preferably up to 5.05 to 1, acid to polyamine compound.

Preferred aspects of the present invention do not employ a salt of (1) a molybdenum oxide, sulfide or oxysulfide and (2) an amide reaction product of a carboxylic acid component and a polyamine component wherein the charge mass ratio (CMR) of the carboxylic acid component to the polyamine component is about 2:1 to 1:1.

Especially preferred aspects of the present invention do not employ any molybdenum compound.

The derivative of a fatty acid and a polyamine, namely a fatty acid amide or a salt of a fatty acid and a polyamine; or any mixture thereof, are incorporated into the selected fuel, as an additive; or into a solvent, to form an additive composition which can be added to a fuel and/or lubricant. Two or more such additives can be added to a fuel, lubricant or solvent separately or in admixture. The additive can be previously diluted with a small amount of a diluent oil such as kerosene or an aromatic solvent to give a concentrated additive solution and the concentrated additive solution can be incorporated into the fuel to be treated. For instance, an additive of the invention can be mixed with a diluent to give a concentrated additive solution containing 1 to 70 weight percent of the additive, and the thus obtained concentrated solution can then be diluted with the fuel and/or lubricant to be treated.

Commercial fuels may include a number of additives which perform a variety of different functions. Depending on the fuel, additives may be used to improve engine performance, fuel handling, fuel stability and contaminant control. Typical additives include antioxidants to prevent oxidation and thus gum forming reactions; stability improvers to prevent sediment formation; metal deactivators to chelate to metal ions and prevent the catalysis thereby of oxidation reactions; cetane improvers to promote oxidation at higher temperatures by the generation of free radicals; octane improvers which prevent pre-ignition or knock in spark ignition engines; dispersants or detergents to prevent deposit formation in the injection system or remove existing deposits; valve seat recession additives; further lubricity improvers if wished, particularly to prevent wear; as well as corrosion inhibitors, anti-static additives, dehazers and demulsifiers, cold-flow improvers, anti-icing additives; pour-point improvers, CFPP improvers, wax anti-settling additives, anti-foams, dyes, markers, odour masks and drag reducers. For reasons of convenience and accurate dosing these are preferably provided in an additive composition with a fatty acid amide or fatty acid amine salt but could if wished be added separately.

There are no specific limitations with respect to the fuel for which the invention is employable. The fuel may, for example, be diesel, gasoline, with or without oxygenates, including ethers and alcohols; or may itself be an alcohol, for example methanol or ethanol. Suitably the fuel is any fuel which may be used in compression ignition engines and spark ignition engines.

A gasoline fuel which may be used in the present invention is a liquid fuel for use with spark ignition engines (typically or preferably containing primarily or only C4-C12 hydrocarbons) and satisfying international gasoline specifications, such as ASTM D-439 and EN228. The term includes blends of distillate hydrocarbon fuels with oxygenated components such as ethanol, as well as the distillate fuels themselves.

A diesel fuel which may be used in the present invention may comprise a petroleum-based fuel oil, especially a middle distillate fuel oil. Such distillate fuel oils generally boil within the range of from 110° C. to 500° C., e.g. 150° C. to 400° C. The diesel fuel may comprise atmospheric distillate or vacuum distillate, cracked gas oil, or a blend in any proportion of straight run and refinery streams such as thermally and/or catalytically cracked and hydro-cracked distillates.

A diesel fuel which may be used in the present invention may comprise non-renewable Fischer-Tropsch fuels such as those described as GTL (gas-to-liquid) fuels, CTL (coal-to-liquid) fuels and OTL (oil sands-to-liquid).

A diesel fuel which may be used in the present invention may comprise a renewable fuel such as a biofuel or biodiesel.

A diesel fuel which may be used in the present invention may comprise 1st generation biodiesel. First generation biodiesel contains esters of, for example, vegetable oils, animal fats and used cooking fats. This form of biodiesel may be obtained by transesterification of oils, for example rapeseed oil, soybean oil, safflower oil, palm 25 oil, corn oil, peanut oil, cotton seed oil, tallow, coconut oil, physic nut oil (Jatropha), sunflower seed oil, used cooking oils, hydrogenated vegetable oils or any mixture thereof, with an alcohol, usually a monoalcohol, in the presence of a catalyst.

A diesel fuel which may be used in the present invention may comprise second generation biodiesel. Second generation biodiesel is derived from renewable resources such as vegetable oils and animal fats and processed, often in the refinery, often using hydroprocessing such as the H-Bio process developed by Petrobras. Second generation biodiesel may be similar in properties and quality to petroleum based fuel oil streams, for example renewable diesel produced from vegetable oils, animal fats etc. and marketed by ConocoPhillips as Renewable Diesel and by Neste as NExBTL.

A diesel fuel which may be used in the present invention may comprise third generation biodiesel. Third generation biodiesel utilises gasification and Fischer-Tropsch technology including those described as BTL (biomass-to-liquid) fuels. Third generation biodiesel does not differ widely from some second generation biodiesel, but aims to exploit the whole plant (biomass) and thereby widens the feedstock base. A diesel fuel which may be used in the present invention may contain blends of any or all of the above diesel fuels.

In some embodiments a diesel fuel which may be used in the present invention may be a blended diesel fuel comprising bio-diesel. In such blends the bio-diesel may be present in an amount of, for example up to 0.5%, up to 1%, up to 2%, up to 3%, up to 4%, up to 5%, up to 10%, up to 20%, up to 30%, up to 40%, up to 50%, up to 60%, up to 70%, up to 80%, up to 90%, up to 95% or up to 99%.

In some embodiments a diesel fuel which may be used in the present invention may comprise a secondary fuel, for example ethanol and/or an alcohol and/or ether as an oxygenate. Preferably however the diesel fuel does not contain ethanol.

Preferably, a diesel fuel which may be used in the present invention has a sulphur content of at most 0.05% by weight, more preferably of at most 0.035% by weight, especially of at most 0.015%. Fuels with even lower levels of sulphur are also suitable such as, fuels with less than 50 ppm sulphur by weight, preferably less than 20 ppm, for example 10 ppm or less.

Examples of diesel fuels to which the invention is applicable are diesel fuels which have been treated to reduce the sulphur content to have the above content. Preferred diesel fuels are those which are as defined in BS EN 590 or ASTM D975

A suitable lubricant may be a mineral base oil and/or a synthesized base oil that are commonly used in lubricants.

The mineral base oil may be, for example, a lubricant base oil prepared by atmospheric distilling crude oil, further distilling the atmospheric residue under reduced pressure, and refining the resulting lubricant fraction by at least one of solvent deasphalting, solvent extraction, hydrocracking, solvent dewaxing, and hydrorefining; or a wax-isomerized mineral oil or a lubricant base oil prepared by isomerization of GTL WAX (gas-to-liquid wax).

The sulphur content of the mineral base oil is usually not higher than 1% wt/wt, preferably not higher than 0.2% wt/wt, more preferably not higher than 0.1% wt/wt, still more preferably not higher than 0.005% wt/wt.

Examples of the synthetic base oil may include polybutene or hydrides thereof; poly-alpha-olefins, such as 1-octene oligomer or 1-decene oligomer, or hydrides thereof; diesters, such as ditridecyl glutarate, di-2-ethylhexyl adipate, diisodecyl adipate, ditridecyl adipate, or di-2-ethylhexyl sebacate; polyol esters, such as neopentyl glycol esters, trimethylolpropane caprylate, trimethylolpropane pelargonate, pentaerythritol-2-ethylhexanoate, or pentaerythritol pelargonate; aromatic synthetic oils, such as alkylnaphthalene, alkylbenzene, or aromatic esters; and mixtures of two or more of these.

A lubricant used in the present invention may be the above-mentioned mineral base oil, above-mentioned synthetic base oil, or a mixture of two or more oils selected from these. For example, one or more mineral base oils, one or more synthetic base oils, or a mixed oil of one or more mineral base oils and one or more synthetic oils, may be used.

A lubricant used in the present invention may include one or more lubricant additives, in addition to the carboxylic-polyamine compound of the present invention, Further lubricant additives may for example be selected from antioxidants, detergents, anti-wear agents, metal deactivators, rust inhibitors, friction modifiers, anti-foam agents, viscosity index improvers, and demulsifying/emulsifying agents.

In addition to the additive mentioned above, which is a derivative of a fatty acid and a polyamine, the invention may employ one or more additional friction modifiers, that is, one or more additional friction modifiers which are not derivatives of fatty acids and polyamines. Such additional friction modifiers are called hereinafter AFMs for brevity and clarity.

AFMs known in the art include the following:

-   -   Fatty acids, for example aliphatic fatty acids having 12 to 30         carbon atoms, preferably 14 to 30 carbon atoms; especially such         fatty acids which are named above     -   Esters of fatty acids     -   Aliphatic amines     -   Aliphatic esters     -   Aromatic esters     -   Aliphatic ethers     -   Polyethers     -   Polyetheramines     -   Polyhydric aliphatic alcohols     -   Hydrocarbyl succinic acids and derivatives     -   Reaction products of acylating agents and amines, for example         poly(isobutenylsuccinimides) (PIBSIs)     -   N,N-bis(hydroxyalkyl)-alkylamine     -   Hydroxyl containing esters of mono carboxylic acid and polyols     -   Alkylalkoxy amides     -   Polyalkylene amines     -   Mannich bases based on tertiary alky substituted phenol and         C1-20 primary amines or polyalkylene amines     -   Polyisobutylene amines     -   Mixtures of esters (e.g. as defined herein) and polyisobutylene         amines     -   Mixtures of esters (e.g. as defined herein) and polyetheramines.

Examples of sources of information about AFMs which are believed to be of use in the present invention are as follows. Any of these may be regarded as a preferred feature of the present invention and so may be claimed, in conjunction with any of the first, second and third aspects given above. The patent specifications mentioned may be consulted if more information is required.

U.S. Pat. No. 4,396,517: the AFMs in this disclosure of interest in the present invention are Mannich bases based on C4-20 tertiary alkyl substituted phenol, aldehyde and C1-20 primary amines. An example includes the di(mono-cocoamine) mannich base of p-tert-butylphenol, paraformaldehyde and cocoamine.

-   -   the phenol may suitably be of the formula

wherein R is preferably hydrogen, but can be a C1 to C30 hydrocarbyl group, which may be an alkyl, alkenyl, aryl, alkaryl or aralkyl group and R¹ is preferably a tertiary hydrocarbyl group, preferably alkyl or alkenyl containing 4 to 20 carbon atoms. Representative phenols that may be used are p-tert-butylphenols, p-tert-octylphenol, p-tert-dodecyl-phenol, p-tert-hexadecylphenol.

-   -   the aldehyde contemplated may be an aliphatic aldehydes,         typified by formaldehyde or paraformaldehyde, acetaldehyde, and         aldol (beta-hydroxy butyraldehyde); aromatic aldehydes, such as         benzaldehyde and heterocyclic aldehydes, such as furfural. The         aldehyde may contain a substituent group such as hydroxyl,         halogen, nitro and the like. In short, any substituent can be         used which does not take a major part in the reaction.         Preference, however, is given to the aliphatic aldehydes,         formaldehyde being particularly preferred.     -   the amine may contain a primary amino group. Preferably, these         include saturated and unsaturated aliphatic amines containing 1         to 20 carbon atoms, for example polyalkylenepolyamines of the         formula NH_(n)(R²NH)_(n)H.

U.S. Pat. No. 4,427,562: the AFMs in this disclosure of interest in the present invention are N-alkoxyalkyl amides represented by the following formula:

wherein R is a hydrocarbyl group or a mixture of hydrocarbyl groups containing from about 5-30 carbon atoms; R¹ is a hydrocarbyl group containing from about 2-10 carbon atoms; and R² is hydrogen. The N-alkoxyalkyl amides may be formed by the reaction of primary alkoxyalkylamines with carboxylic acids such as formic acid, or alternatively by ammonolysis of the appropriate formate ester.

U.S. Pat. No. 4,617,026: the AFMs in this disclosure of interest in the present invention are hydroxyl-containing esters of a monocarboxylic acid and a glycol or trihydric alcohol, said ester additive having at least one free hydroxyl group. More particularly, the AFM may be an ester of a monocarboxylic acid and a glycol or trihydric alcohol, said acid having about 12 to about 30 carbon atoms, said glycol being an alkane diol or oxa-alkane diol wherein said alkane is a straight chain hydrocarbon of about 2 to about 5 carbon atoms and said trihydric alcohol has a straight chain hydrocarbon structure of about 3 to about 6 carbon atoms, said ester additive having at least one free hydroxyl group. Examples include glycerol monooleate and glycerol dioleate.

WO9835000: the AFMs in this disclosure of interest in the present invention are C7+ primary, linear alcohols, preferably C12-C24. The alcohol may be added in an amount of at least about 0.05 to 0.5 wt % fuel.

U.S. Pat. No. 6,203,584: the AFMs in this disclosure of interest in the present invention are (1) a fuel-soluble aliphatic hydrocarbyl-substituted amine having at least one basic nitrogen atom where the hydrocarbyl group has a number average molecular weight of about 700 to 3,000, and (2) a poly(oxyalkylene) amine having at least one basic nitrogen atom and a sufficient number of oxyalkylene units to render the poly(oxyalkylene) amine soluble in hydrocarbons boiling in the gasoline range; and (b) an ester of a carboxylic acid and a polyhydric alcohol, wherein the carboxylic acid has from one to about four carboxylic acid groups and from about 8 to about 50 carbon atoms and the polyhydric alcohol has from about 2 to about 50 carbon atoms and from about 2 to about 6 hydroxy groups.

Examples comprise combinations of pibamine or polyetheramine with glycerol monooleate or pentaerythritol mono oleate

WO 01/72930: the AFMs in this disclosure of interest in the present invention are the reaction products of a natural or synthetic oil, for example a C6-C22 fatty acid ester, for example an oil is selected from the group consisting of beef tallow oil, lard oil, palm oil, castor oil, cottonseed oil, corn oil, peanut oil, soybean oil, sunflower oil, olive oil, whale oil, menhaden oil, sardine oil, coconut oil, palm kernel oil, babassu oil, rape oil and soya oil: and at least one alkanolamine preferably selected from the group consisting of monoethanolamine, diethanolamine, propanolamine, isopropanolamine, dipropanolamine, di-isopropanolamine, butanolamines, aminoethylaminoethanol and mixtures thereof. For example the reaction product of coconut oil and diethanolamine.

US2004/0154218: the AFMs in this disclosure of interest in the present invention include polyalkylene oxides, preferably derived from an alkylene oxide wherein the alkylene group has from about 2 to 5 carbon atoms. Preferably, the polyalkylene-oxide is an oligomer or polymer of an alkylene oxide selected from the group consisting of ethylene oxide, propylene oxide, butylene oxide, and pentylene oxide. Ethylene oxide and propylene oxide are particularly preferred. In addition, mixtures of alkylene oxides are desirable in which, for example, a mixture of ethylene oxide and propylene oxide may be used. A respective molar ratio of from about 1:5 to 5:1 may be used in the case of a mixture of ethylene oxide and propylene oxide. The polyalkylene-oxide may also be end-capped with an ether or ester function to give, for example, a mono-alkoxy polyalkylene-oxide, such as n-butoxy polypropylene glycol. A desirable number of moles of the polyalkylene-oxide will be in the range of from about 3 to 50 moles of alkylene oxide per 1 mole of hydrocarbyl amide. More preferably, the range of from about 3 to 20 moles is particularly desirable. Most preferably, the range of from about 4 to 15 moles is most preferable.

EP0020037: the AFMs in this disclosure of interest in the present invention are oil-soluble aliphatic hydrocarbyl-substituted succinimide or succinamide materials, wherein the hydrocarbyl group contains about 12 to 36 carbon atoms and is preferably derived from an isomerized straight chain alpha-olefin.

Alternatively: we may define suitable and related AFMs as being the reaction product of a carboxylic acid-derived acylating agent and an amine; for example PIBSA, suitably having a hydrocarbyl substituent with a number average molecular weight (Mn) of between 250 to 1500, a polyalkylene polyamine, preferably with 1 to 6 carbon atoms and preferably with 2 to 8 nitrogen atoms, for example ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, tri(tri-methylene)tetramine, pentaethylenehexamine, aminoethylethanolamine, hexaethyleneheptamine or 1,2-propylenediamine. Preferably the molar ratio of acylating agent:amino compound is preferably from 2:1 to 1:1.

Alternatively: a number of suitable acylated, nitrogen-containing compounds having a hydrocarbyl substituent of at least 8 carbon atoms and made by reacting a carboxylic acid acylating agent with an amino compound are known to those skilled in the art. In such compositions the acylating agent is linked to the amino compound through an imido, amido, amidine or acyloxy ammonium linkage. The hydrocarbyl substituent of at least 8 carbon atoms may be in either the carboxylic acid acylating agent derived portion of the molecule or in the amino compound derived portion of the molecule, or both. Preferably, however, it is in the acylating agent portion. The acylating agent can vary from formic acid and its acylating derivatives to acylating agents having high molecular weight aliphatic substituents of up to 5,000, 10,000 or 20,000 carbon atoms. The amino compounds can vary from ammonia itself to amines typically having aliphatic substituents of up to about 30 carbon atoms, and up to 11 nitrogen atoms.

A preferred class of acylated amino compounds suitable for use in the present invention are those formed by the reaction of an acylating agent having a hydrocarbyl substituent of at least 8 carbon atoms and a compound comprising at least one primary or secondary amine group. The acylating agent may be a mono- or polycarboxylic acid (or reactive equivalent thereof) for example a substituted succinic, phthalic or propionic acid and the amino compound may be a polyamine or a mixture of polyamines, for example a mixture of ethylene polyamines. Alternatively the amine may be a hydroxyalkyl-substituted polyamine. The hydrocarbyl substituent in such acylating agents preferably comprises at least 10, more preferably at least 12, for example 30 or 50 carbon atoms. It may comprise up to about 200 carbon atoms. Preferably the hydrocarbyl substituent of the acylating agent has a number average molecular weight (Mn) of from 160 to 5000, preferably from 170 to 2800, for example from 250 to 1500, preferably from 500 to 1500 and more preferably 500 to 1100. An Mn of 700 to 1300 is especially preferred. In a particularly preferred embodiment, the hydrocarbyl substituent has a number average molecular weight of 700-1000.

Illustrative of hydrocarbyl substituent based groups containing at least eight carbon atoms are n-octyl, n-decyl, n-dodecyl, tetrapropenyl, n-octadecyl, oleyl, chloroctadecyl, triicontanyl, etc. The hydrocarbyl based substituents may be made from homo- or interpolymers (e.g. copolymers, terpolymers) of mono- and di-olefins having 2 to 10 carbon atoms, for example ethylene, propylene, butane-1, isobutene, butadiene, isoprene, 1-hexene, 1-octene, etc. Preferably these olefins are 1-monoolefins. The hydrocarbyl substituent may also be derived from the halogenated (e.g. chlorinated or brominated) analogs of such homo- or interpolymers. Alternatively the substituent may be made from other sources, for example monomeric high molecular weight alkenes (e.g. 1-tetra-contene) and chlorinated analogs and hydrochlorinated analogs thereof, aliphatic petroleum fractions, for example paraffin waxes and cracked and chlorinated analogs and hydrochlorinated analogs thereof, white oils, synthetic alkenes for example produced by the Ziegler-Natta process (e.g. poly(ethylene) greases) and other sources known to those skilled in the art. Any unsaturation in the substituent may if desired be reduced or eliminated by hydrogenation according to procedures known in the art.

The term “hydrocarbyl” as used within this specification denotes a group having a carbon atom directly attached to the remainder of the molecule and having a predominantly aliphatic hydrocarbon character. Suitable hydrocarbyl based groups may contain non-hydrocarbon moieties. For example they may contain up to one non-hydrocarbyl group for every ten carbon atoms provided this non-hydrocarbyl group does not significantly alter the predominantly hydrocarbon character of the group. Those skilled in the art will be aware of such groups, which include for example hydroxyl, halo (especially chloro and fluoro), alkoxyl, alkyl mercapto, alkyl sulphoxy, etc. Preferred hydrocarbyl based substituents are purely aliphatic hydrocarbon in character and do not contain such groups.

The hydrocarbyl-based substituents are preferably predominantly saturated, that is, they contain no more than one carbon-to-carbon unsaturated bond for every ten carbon-to-carbon single bonds present. Most preferably they contain no more than one carbon-to-carbon non-aromatic unsaturated bond for every 50 carbon-to-carbon bonds present.

Preferred hydrocarbyl-based substituents are poly-(isobutene)s known in the art.

Conventional polyisobutenes and so-called “highly-reactive” polyisobutenes are suitable for use in the invention. Highly reactive polyisobutenes in this context are defined as polyisobutenes wherein at least 50%, preferably 70% or more, of the terminal olefinic double bonds are of the vinylidene type as described in EP0565285. Particularly preferred polyisobutenes are those having more than 80 mol % and up to 100 mol % of terminal vinylidene groups such as those described in EP1344785.

Amino compounds useful for reaction with these acylating agents include the following:

(1) polyalkylene polyamines of the general formula:

(R³)₂N[U—N(R³)]_(n)R³

wherein each R³ is independently selected from a hydrogen atom, a hydrocarbyl group or a hydroxy-substituted hydrocarbyl group containing up to about 30 carbon atoms, with proviso that at least one R³ is a hydrogen atom, n is a whole number from 1 to 10 and U is a C1-18 alkylene group. Preferably each R³ is independently selected from hydrogen, methyl, ethyl, propyl, isopropyl, butyl and isomers thereof. Most preferably each R³ is ethyl or hydrogen. U is preferably a C1-4 alkylene group, most preferably ethylene.

Specific examples of polyalkylene polyamines (1) include ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, tri(tri-methylene)tetramine, pentaethylenehexamine, hexaethylene-heptamine, 1,2-propylenediamine, and other commercially available materials which comprise complex mixtures of polyamines. For example, higher ethylene polyamines optionally containing all or some of the above in addition to higher boiling fractions containing 8 or more nitrogen atoms etc.

Specific examples of polyalkylene polyamines (1) which are hydroxyalkyl-substituted polyamines include N-(2-hydroxyethyl)ethylene diamine, N,N′-bis(2-hydroxyethyl) ethylene diamine, N-(3-hydroxybutyl) tetramethylene diamine, etc.

(2) heterocyclic-substituted polyamines including hydroxyalkyl-substituted polyamines wherein the polyamines are as described above and the heterocyclic substituent is selected from nitrogen-containing aliphatic and aromatic heterocycles, for example piperazines, imidazolines, pyrimidines, morpholines, etc.

Specific examples of the heterocyclic-substituted polyamines (2) are N-2-aminoethyl piperazine, N-2 and N-3 amino propyl morpholine, N-3(dimethyl amino) propyl piperazine, 2-heptyl-3-(2-aminopropyl) imidazoline, 1,4-bis(2-aminoethyl) piperazine, 1-(2-hydroxy ethyl) piperazine, and 2-heptadecyl-1-(2-hydroxyethyl)-imidazoline, etc.

(3) aromatic polyamines of the general formula:

Ar(NR³ ₂)_(y)

wherein Ar is an aromatic nucleus of 6 to 20 carbon atoms, each R³ is as defined above and y is from 2 to 8.

Specific examples of the aromatic polyamines (3) are the various isomeric phenylene diamines, the various isomeric naphthalene diamines, etc.

4) The amine reactant may alternatively be a compound of general formula R²R³NH where each of R² and R³ independent represents a hydrocarbyl group (as defined herein), preferably a hydrocarbon group (as defined herein), or a hydrogen atom.

Preferably at least one of R² and R³ represents a hydrocarbyl group.

Preferably both R² and R³ represent a hydrocarbyl group.

Suitable terminal groups of a hydrocarbyl group R² and/or R³ may include —CH₃, ═CH₂, —OH, —C(O)OH and derivatives thereof. Suitable derivatives include esters and ethers. Preferably a hydrocarbyl group R² and/or R³ does not contain a terminal amine.

A preferred hydrocarbyl group for each of R² and R³ is a group of the formula

—[R⁴NH]_(p)R⁵X

wherein R⁴ is an alkylene group having from 1 to 10 carbons, preferably from 1 to 5, preferably 1 to 3 carbons, preferably 2 carbons; wherein R⁵ is an alkylene group having from 1 to 10 carbons, preferably from 1 to 5, preferably 1 to 3 carbons, preferably 2 carbons; wherein p is an integer from 0 to 10; wherein X is selected from —CH₃, —CH₂═CH₂, —OH, and —C(O)OH.

A preferred hydrocarbyl group for each of R² and R³ is a group of the formula

—[(CH₂)_(q)NH]_(p)(CH₂)_(r)X

wherein p is an integer from 0 to 10, preferably 1 to 10, preferably from 1 to 5, preferably from 1 to 3, preferably 1 or 2; wherein q is an integer from 1 to 10, preferably 1 to 10, preferably from 1 to 5, preferably from 1 to 3, preferably 1 or 2; wherein r is an integer from 1 to 10, preferably 1 to 10, preferably from 1 to 5, preferably from 1 to 3, preferably 1 or 2; and wherein X is selected from —CH₃, —CH₂═CH₂, —OH, and —C(O)OH.

Preferably X is —CH₃, or —OH.

Further amines which may be used in this invention include compounds derived from amines selected from ammonia, butylamine, aminoethylethanolamine, aminopropan-2-ol, 5-aminopentan-1-ol, 2-(2-aminoethoxy)ethanol, monoethanolamine, 3-aminopropan-1-ol, 2-((3-aminopropyl)amino)ethanol, dimethylaminopropylamine, and N-(alkoxyalkyl)-alkanediamines including N-(octyloxyethyl)-1,2-diaminoethane and N-(decyloxypropyl)-N-methyl-1,3-diaminopropane.

Specific examples of amines which may be used in this invention and having a tertiary amino group can include but are not limited to: N,N-dimethyl-aminopropylamine, N,N-diethyl-aminopropylamine, N,N-dimethyl-amino ethylamine. The nitrogen or oxygen containing compounds capable of condensing with the acylating agent and further having a tertiary amino group can further include amino alkyl substituted heterocyclic compounds such as 1-(3-aminopropyl)imidazole and 4-(3-aminopropyl)morpholine, 1-(2-aminoethyl)piperidine, 3,3-diamino-N-methyldi-propylamine, and 3′3-aminobis(N,N-dimethylpropylamine). Other types of compounds capable of condensing with the acylating agent and having a tertiary amino group include alkanolamines including but not limited to triethanolamine, trimethanolamine, N,N-dimethylaminopropanol, N,N-diethylaminopropanol, N,N-diethylaminobutanol, N,N,N-tris(hydroxyethyl)amine and N,N,N-tris(hydroxymethyl)amine.

Many patents have described useful acylated nitrogen compounds including U.S. Pat. Nos. 3,172,892; 3,219,666; 3,272,746; 3,310,492; 3,341,542; 3,444,170; 3,455,831; 3,455,832; 3,576,743; 3,630,904; 3,632,511; 3,804,763, 4,234,435 and U.S. Pat. No. 6,821,307. A preferred acylated nitrogen-containing compound of this class is that made by reacting a poly(isobutene)-substituted succinic acid-derived acylating agent (e.g., anhydride, acid, ester, etc.) wherein the poly(isobutene) substituent has between about 12 to about 200 carbon atoms and the acylating agent has from 1 to 5, preferably from 1 to 3, preferably 1 or 2, succinic-derived acylating groups; with a mixture of ethylene polyamines having 3 to about 9 amino nitrogen atoms, preferably about 3 to about 8 nitrogen atoms, per ethylene polyamine and about 1 to about 8 ethylene groups. These acylated nitrogen compounds are formed by the reaction of a molar ratio of acylating agent:amino compound of from 10:1 to 1:10, preferably from 5:1 to 1:5, more preferably from 2:1 to 1:2 and most preferably from 2:1 to 1:1. In especially preferred embodiments, the acylated nitrogen compounds are formed by the reaction of acylating agent to amino compound in a molar ratio of from 1.8:1 to 1:1.2, preferably from 1.6:1 to 1:1.2, more preferably from 1.4:1 to 1:1.1 and most preferably from 1.2:1 to 1:1. This type of acylated amino compound and the preparation thereof is well known to those skilled in the art and are described in the above-referenced US patents.

Another type of acylated nitrogen compound belonging to this class is that made by reacting the afore-described alkylene amines with the afore-described substituted succinic acids or anhydrides and aliphatic mono-carboxylic acids having from 2 to about 22 carbon atoms. In these types of acylated nitrogen compounds, the mole ratio of succinic acid to mono-carboxylic acid ranges from about 1:0.1 to about 1:1. Typical of the monocarboxylic acid are formic acid, acetic acid, dodecanoic acid, butanoic acid, oleic acid, stearic acid, the commercial mixture of stearic acid isomers known as isostearic acid, tolyl acid, etc. Such materials are more fully described in U.S. Pat. Nos. 3,216,936 and 3,250,715.

A further type of acylated nitrogen compound suitable for use in the present invention is the product of the reaction of a fatty monocarboxylic acid of about 12-30 carbon atoms and the afore-described alkylene amines, typically, ethylene, propylene or trimethylene polyamines containing 2 to 8 amino groups and mixtures thereof. The fatty mono-carboxylic acids are generally mixtures of straight and branched chain fatty carboxylic acids containing 12-30 carbon atoms. Fatty dicarboxylic acids could also be used. A widely used type of acylated nitrogen compound is made by reacting the afore-described alkylene polyamines with a mixture of fatty acids having from 5 to about 30 mole percent straight chain acid and about 70 to about 95 percent mole branched chain fatty acids. Among the commercially available mixtures are those known widely in the trade as isostearic acid. These mixtures are produced as a by-product from the dimerization of unsaturated fatty acids as described in U.S. Pat. Nos. 2,812,342 and 3,260,671.

The branched chain fatty acids can also include those in which the branch may not be alkyl in nature, for example phenyl and cyclohexyl stearic acid and the chloro-stearic acids. Branched chain fatty carboxylic acid/alkylene polyamine products have been described extensively in the art. See for example, U.S. Pat. Nos. 3,110,673; 3,251,853; 3,326,801; 3,337,459; 3,405,064; 3,429,674; 3,468,639; 3,857,791. These patents are referenced for their disclosure of fatty acid/polyamine condensates for their use in lubricating oil formulations.

Suitably the molar ratio of the acylating group of an acylating agent defined above and the reacting amine group of said amine is in the range 0.5-5:1, preferably 0.8-2.2:1. At a ratio of 1:1 the reaction product is called mono-PIBSI, and at a ratio of 2:1 it is called bis-PIBSI and requires a polyamine as reactant.

US2005/223630: the AFMS in this disclosure of interest in the present invention are the reaction products of a carboxylic acid-derived acylating agent and an amine; for example a polyisobutenyl succinimide.

An alternative or additional AFM of interest in the present invention may additionally comprise additional components selected from:

-   -   a) carrier oils comprising an optionally esterified polyether,     -   b) polyetheramines,     -   c) hydrocarbyl-substituted amines wherein the hydrocarbyl         substituent is substantially aliphatic and contains at least 8         carbon atoms,     -   d) nitrogen-containing condensates of a phenol, aldehyde and         primary or secondary amine,     -   e) aromatic esters of a polyalkylphenoxyalkanol.

Compounds a) to e) may be described further as follows:

a) Carrier Oil

A carrier oil may have any suitable molecular weight. A preferred molecular weight is in the range 500 to 5000.

In a preferred aspect the polyether carrier oil is a mono end-capped polypropylene glycol. Preferably the end cap is a group consisting of or containing a hydrocarbyl group having up to 30 carbon atoms. More preferably the end cap is or comprises an alkyl group having from 4 to 20 carbon atoms or from 12 to 18 carbon atoms.

The alkyl group may be branched or straight chain. Preferably it is a straight chain group.

Further hydrocarbyl end capping groups include alkyl-substituted phenyl, especially where the alkyl substituent(s) is or are alkyl groups of 4 to 20 carbon atoms, preferably 8 to 12, preferably straight chain.

The hydrocarbyl end capping group may be attached to the polyether via a linker group. Suitable end cap linker groups include an ether oxygen atom (—O—), an amine group (—NH—), an amide group (—CONH—), or a carbonyl group —(C═O)—.

In a preferred embodiment the carrier oil is a polypropyleneglycol monoether of the formula:

where R⁶ is straight chain C₁-C₃₀ alkyl, preferably C₄-C₂₀ alkyl, preferably C₁₂-C₁₈ alkyl; and n is an integer of from 10 to 50, preferably 10 to 30, more preferably 12 to 20.

Such alkyl polypropyleneglycol monoethers are obtainable by the polymerisation of propylene oxide using an aliphatic alcohol, preferably a straight chain primary alcohol of to 20 carbon atoms, as an initiator. If desired a proportion of the propyleneoxy units may be replaced by units derived from other C₂-C₆ alkylene oxides, e.g. ethylene oxide or isobutylene oxide, and are to be included within the term “polypropyleneglycol”. The initiator may also be a phenol or alkyl phenol of the formula R⁷OH, a hydrocarbyl amine or amide of the formula R⁷NH₂ or R⁷CONH, respectively, where R⁷ is C₁-C₃₀ hydrocarbyl group, preferably a saturated aliphatic or aromatic hydrocarbyl group such as alkyl, phenyl or phenalkyl etc. Preferred initiators include long chain alkanols giving rise to the long chain polypropyleneglycol monoalkyl ethers.

In a further aspect the polypropyleneglycol may be an ester (R⁶COO) group where R⁶ is defined above. In this aspect the carrier oil may be a polypropyleneglycol monoester of the formula

where R⁶ and n are as defined above and R⁸ is a C₁-C₃₀ hydrocarbyl group, preferably an aliphatic hydrocarbyl group, and more preferably C₁-C₁₀ alkyl.

b) Polyetheramines

Suitable hydrocarbyl-substituted polyoxyalkylene amines or polyetheramines are described in the literature (for example U.S. Pat. No. 6,217,624 and U.S. Pat. No. 4,288,612) and have the general formula:

or a fuel-soluble salt thereof; wherein R is a hydrocarbyl group having from about 1 to about 30 carbon atoms; R1 and R2 are each independently hydrogen or lower alkyl having from about 1 to about 6 carbon atoms and each R1 and R2 is independently selected in each —O—CHR1-CHR2- unit; A is amino, N-alkyl amino having about 1 to about 20 carbon atoms in the alkyl group, N,N-dialkyl amino having about 1 to about 20 carbon atoms in each alkyl group, or a polyamine moiety having about 2 to about 12 amine nitrogen atoms and about 2 to about 40 carbon atoms; x is an integer from about 5 to about 100; and y is 0 or 1. In the formula, above, R is suitably a hydrocarbyl group having from about 1 to about 30 carbon atoms. Preferably, R is an alkyl or alkylphenyl group. More preferably, R is an alkylphenyl group, wherein the alkyl moiety is a straight or branched chain alkyl of from about 1 to about 24 carbon atoms.

Preferably, one of R1 and R2 is lower alkyl of 1 to 4 carbon atoms, and the other is hydrogen. More preferably, one of R1 and R2 is methyl or ethyl, and the other is hydrogen.

In general, A is amino, N-alkyl amino having from about 1 to about 20 carbon atoms in the alkyl group, preferably about 1 to about 6 carbon atoms, more preferably about 1 to about 4 carbon atoms; N,N-dialkyl amino having from about 1 to about 20 carbon atoms in each alkyl group, preferably about 1 to about 6 carbon atoms, more preferably about 1 to about 4 carbon atoms; or a polyamine moiety having from about 2 to about 12 amine nitrogen atoms and from about 2 to about 40 carbon atoms, preferably about 2 to 12 amine nitrogen atoms and about 2 to 24 carbon atoms. More preferably, A is amino or a polyamine moiety derived from a polyalkylene polyamine, including alkylene diamine. Most preferably, A is amino or a polyamine moiety derived from ethylene diamine or diethylene triamine.

Preferably, x is an integer from about 5 to about 50, more preferably from about 8 to about 30, and most preferably from about 10 to about 25.

The polyetheramines will generally have a molecular weight in the range from about 600 to about 10,000.

Fuel-soluble salts of the compounds of formula I can be readily prepared for those compounds containing an amino or substituted amino group and such salts are contemplated to be useful for preventing or controlling engine deposits. Suitable salts include, for example, those obtained by protonating the amino moiety with a strong organic acid, such as an alkyl- or arylsulfonic acid. Preferred salts are derived from toluenesulfonic acid and methanesulfonic acid.

Other suitable polyetheramines are those taught in U.S. Pat. No. 5,089,029 and U.S. Pat. No. 5,112,364.

c) Hydrocarbyl-Substituted Amines

Hydrocarbyl-substituted amines suitable for use in the present invention are well known to those skilled in the art and are described in a number of patents. Among these are U.S. Pat. Nos. 3,275,554; 3,438,757; 3,454,555; 3,565,804; 3,755,433 and 3,822,209. These patents describe suitable hydrocarbyl amines for use in the present invention including their method of preparation.

d) Nitrogen-Containing Condensates of Phenols, Aldehydes, and Amino Compounds

Phenol/aldehyde/amine condensates useful as AFMs in the present invention include those generically referred to as Mannich condensates. Such compounds can be made by reacting simultaneously or sequentially at least one active hydrogen compound for example a hydrocarbon-substituted phenol (e.g., an alkyl phenol wherein the alkyl group has at least an average of about 8 to 200; preferably at least 12 up to about 200 carbon atoms), having at least one hydrogen atom bonded to an aromatic carbon, with at least one aldehyde or aldehyde-producing material (typically formaldehyde or a precursor thereof) and at least one amino or polyamino compound having at least one NH group. The amino compounds include primary or secondary monoamines having hydrocarbon substituents of 1 to 30 carbon atoms or hydroxyl-substituted hydrocarbon substituents of 1 to about 30 carbon atoms. Another type of typical amino compound are the polyamines described above in relation to acylated nitrogen-containing compounds.

One class of preferred nitrogen containing detergent for use as an AFM in the present invention are those formed by a Mannich reaction between:

(a) an aldehyde; (b) a polyamine; and (c) an optionally substituted phenol.

Any aldehyde may be used as aldehyde component (a) but preferred are aliphatic aldehydes. Preferably the aldehyde has 1 to 10 carbon atoms, preferably 1 to 6 carbon atoms, more preferably 1 to 3 carbon atoms. Most preferably the aldehyde is formaldehyde.

Polyamine component (b) may be selected from any compound including two or more amine groups. Preferably the polyamine is a polyalkylene polyamine. Suitable polyalkylene polyamines are as previously defined herein.

Preferably the polyamine has 1 to 15 nitrogen atoms, preferably 1 to 10 nitrogen atoms, more preferably 3 to 8 nitrogen atoms.

Preferably the polyamine is selected from ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, hexaethyleneheptamine, and heptaethyleneoctamine. Most preferably it is tetraethylenepentamine or ethylene diamine.

Commercially available sources of polyamines typically contain mixtures of isomers and/or oligomers, and products prepared from these commercially available mixtures fall within the scope of the present invention.

Optionally substituted phenol component (c) may be substituted with 0 to 4 groups on the aromatic ring (in addition to the phenol OH). For example it may be a tri- or di-substituted phenol. Most preferably component (c) is a mono-substituted phenol. Substitution may be at the ortho, and/or meta, and/or para position(s).

Preferably the phenol component (c) carries one or more optionally substituted alkyl substituents. Preferably the component (c) is a monoalkyl phenol, especially a para-substituted monoalkyl phenol.

In some preferred embodiments component (c) comprises an alkyl substituted phenol in which the phenol carries one or more alkyl chains having a total of less than 28 carbon atoms, preferably less than 24 carbon atoms, preferably less than 20 carbon atoms, more preferably less than 18 carbon atoms, preferably less than 16 carbon atoms and most preferably less than 14 carbon atoms.

For example component (c) may have alkyl substituents having from 4 to 20 carbons atoms, preferably 6 to 18, more preferably 8 to 16, especially 10 to 14 carbon atoms. In some particularly preferred embodiments, component (c) is a phenol having a C12 alkyl substituent.

In other preferred embodiments component (c) is substituted with a larger alkyl chain, for example those having in excess of 20 carbon atoms. Particularly preferred compounds are those in which the phenol is substituted with a hydrocarbyl residue made from homo or interpolymers (e.g. copolymers, terpolymers) of mono- and di-olefins having 2 to 10 carbon atoms, for example ethylene, propylene, butane-1, isobutene, butadiene, isoprene, 1-hexene, 1-octene, etc. Preferably these olefins are 1-monoolefins. The hydrocarbyl substituent may also be derived from the halogenated (e.g. chlorinated or brominated) analogs of such homo- or interpolymers. Alternatively the substituent may be made from other sources which are well known to those skilled in the art.

Especially preferred are phenols substituted with a polyisobutene residue of molecular weight of between 250 and 5000, for example between 500 and 1500, preferably between 650 and 1200, most preferably between 700 and 1000.

Suitable compounds include the reaction product obtained by reacting components (a), (b) and (c) in a ratio of from 5:1:5 to 0.1:1:0.1, more preferably from 3:1:3 to 0.5:1:0.5.

Components (a) and (b) are preferably reacted in a ratio of from 4:1 to 1:1 (aldehyde:polyamine), preferably from 2:1 to 1:1. Components (a) and (c) are preferably reacted in a ratio of from 4:1 to 1:1 (aldehyde:phenol), more preferably from 2:1 to 1:1.

Especially preferred compounds d) are those formed by reacting components (a), (b) and (c) in a ratio of 1:1:1 or 2:1:2. Mixtures of these compounds may also be used. Typically component (b) comprises a mixture of isomers and/or oligomers. Component (c) may also comprise a mixture of isomers and/or homologues.

e) Aromatic Esters of a Polyalkylphenoxyalkanol

The aromatic ester component which may be employed additive composition is an aromatic ester of a polyalkylphenoxyalkanol and has the following general formula:

or a fuel-soluble salt thereof wherein R is hydroxy, nitro or —(CH2)x-NR5R6, wherein R5 and R6 are independently hydrogen or lower alkyl having 1 to 6 carbon atoms and x is 0 or 1; R1 is hydrogen, hydroxy, nitro or —NR7R8 wherein R7 and R8 are independently hydrogen or lower alkyl having 1 to 6 carbon atoms; R2 and R3 are independently hydrogen or lower alkyl having 1 to 6 carbon atoms; and R4 is a polyalkyl group having an average molecular weight in the range of about 450 to 5,000.

The preferred aromatic ester compounds employed in the present invention are those wherein R is nitro, amino, N-alkylamino, or —CH2NH2 (aminomethyl). More preferably, R is a nitro, amino or —CH2NH2 group. Most preferably, R is an amino or —CH2NH2 group, especially amino. Preferably, R1 is hydrogen, hydroxy, nitro or amino. More preferably, R1 is hydrogen or hydroxy. Most preferably, R1 is hydrogen. Preferably, R4 is a polyalkyl group having an average molecular weight in the range of about 500 to 3,000, more preferably about 700 to 3,000, and most preferably about 900 to 2,500. Preferably, the compound has a combination of preferred substituents.

Preferably, one of R2 and R3 is hydrogen or lower alkyl of 1 to 4 carbon atoms, and the other is hydrogen. More preferably, one of R2 and R3 is hydrogen, methyl or ethyl, and the other is hydrogen. Most preferably, R2 is hydrogen, methyl or ethyl, and R3 is hydrogen.

When R and/or R1 is an N-alkylamino group, the alkyl group of the N-alkylamino moiety preferably contains 1 to 4 carbon atoms. More preferably, the N-alkylamino is N-methylamino or N-ethylamino.

Similarly, when R and/or R1 is an NN-dialkylamino group, each alkyl group of the N,N-dialkylamino moiety preferably contains 1 to 4 carbon atoms. More preferably, each alkyl group is either methyl or ethyl. For example, particularly preferred N,N-dialkylamino groups are N,N-dimethylamino, N-ethyl-N-methylamino and N,N-diethylamino groups.

A further preferred group of compounds are those wherein R is amino, nitro, or —CH2NH2 and R1 is hydrogen or hydroxy. A particularly preferred group of compounds are those wherein R is amino, R1, R2 and R3 are hydrogen, and R4 is a polyalkyl group derived from polyisobutene.

It is preferred that the R substituent is located at the meta or, more preferably, the para position of the benzoic acid moiety, i.e., para or meta relative to the carbonyloxy group. When R1 is a substituent other than hydrogen, it is particularly preferred that this R1 group be in a meta or para position relative to the carbonyloxy group and in an ortho position relative to the R substituent. Further, in general, when R1 is other than hydrogen, it is preferred that one of R or R1 is located para to the carbonyloxy group and the other is located meta to the carbonyloxy group. Similarly, it is preferred that the R4 substituent on the other phenyl ring is located para or meta, more preferably para, relative to the ether linking group.

The aromatic esters e) will generally have a molecular weight in the range from about 700 to about 3,500, preferably from about 700 to about 2,500.

Fuel-soluble salts of the compounds e) can be readily prepared for those compounds containing an amino or substituted amino group and such salts are contemplated to be useful for preventing or controlling engine deposits. Suitable salts include, for example, those obtained by protonating the amino moiety with a strong organic acid, such as an alkyl- or arylsulfonic acid. Preferred salts are derived from toluenesulfonic acid and methanesulfonic acid.

When the R or R1 substituent is a hydroxy group, suitable salts can be obtained by deprotonation of the hydroxy group with a base. Such salts include salts of alkali metals, alkaline earth metals, ammonium and substituted ammonium salts. Preferred salts of hydroxy-substituted compounds include alkali metal, alkaline earth metal and substituted ammonium salts.

Preferred additional friction modifiers are esters and or amides, having hydroxyl functionality such as those derived from mono or poly carboxylic acids and a poly alcohol or alkanolamine. Examples of such AFM's include: glycerol mono oleate; pentaerythritol mono oleate; the reaction product of an animal or vegetable oil or fatty acid or synthetic fatty acid and an alkanolamine such as ethanolamine, diethanolamine or propanolamine; the reaction product of a polyalkylene substituted succinic acid or anhydride and a glycol such as ethylene glycol, propylene glycol or polyalkylene glycol.

A derivative of a fatty acid and a polyamine is an essential element in the use of the invention, whilst an AFM is not, but may often be important in obtaining excellent performance. When an AFM is present the weight ratio of a) a derivative of a fatty acid and a polyamine (total weight when more than one such is present) and b) an AFM (total weight when more than one such is present) is in the proportion 1 to 10000 parts a) to 100 parts b), preferably 10 to 1000 parts a) to 100 parts b), preferably 30 to 500 parts a) to 100 parts b), preferably 50 to 3000 parts a) to 100 parts b).

The amount of the fuel additive of the invention, namely a derivative of a fatty acid and a polyamine, and an AFM when an AFM is present (total amounts of each class) is preferably up to 10,000 ppm in the fuel, preferably up to 1,000 ppm, preferably from 1 to 500 ppm, preferably 10 to 200 ppm, and preferably 15 to 100 ppm.

An important additive which may present in certain preferred embodiments is a dispersant or detergent. This is preferably a nitrogen containing compound. This may suitably be present in the fuel at a treat rate in the range 0.1 to 250 ppm, preferably 1 to 100 ppm (total amount when more then one is present). Some of the AFMs mentioned above also have dispersant or detergency properties, namely:

-   -   Polyethers     -   Polyetheramines     -   Reaction products of acylating agents and amines, for example         poly(isobutenylsuccinimides) (PIBSIs)     -   Polyalkylene amines     -   Mannich bases based on tertiary alky substituted phenol and         C1-20 primary amines or polyalkylene amines     -   Mixtures containing any of these.

Preferred dispersants or detergents include dispersants or detergents of the following categories:

-   -   1. Reaction products of acylating agents and amines, for example         poly(isobutenylsuccinimides and poly(isobutenylsuccinamides),     -   2. polyetheramines,     -   3. hydrocarbyl-substituted amines wherein the hydrocarbyl         substituent is substantially aliphatic and contains at least 8         carbon atoms,     -   4. nitrogen-containing condensates of a phenol, aldehyde and         primary or secondary amine; and     -   5. quaternary ammonium salts.

A carrier oil (as defined above under the heading “a) carrier oil”) above may advantageously be used with a dispersant or detergent, including those of class 1-5 mentioned above.

Preferred dispersants or detergents of preceding numbered categories 2, 3 or 4 are as described above in relation to such compounds as AFMS.

A reaction product of acylating agents and amines, for example poly(isobutenyl succinimides) and poly(isobutenylsuccinamides), is suitably a reaction product of poly(isobutenyl)succinic acid anhydride in which the poly(isobutenyl) moiety is of MW from 650 to 1400; and a polyamine preferably having from 4 to 50 carbon atoms preferably 4 to 20 carbon atoms, and preferably from 2 to 10 nitrogen atoms, preferably 3 to 6 nitrogen atoms. Especially preferred polyamines include ethylene diamine (EDA), diethylene triamine (DETA), triethylene tetramine (TETA), tetraethylene pentamine (TEPA), pentaethylene hexamine (PEHA) and dimethylaminopropylamine (DMAPA).

Suitable quaternary ammonium salts are the reaction products of compounds as described in immediately preceding sections 1, 3 and 4, which further comprise a tertiary amine group; and a quaternizing agent. The quaternizing agent may suitably be selected from the group consisting of dialkyl sulphates; an ester of a carboxylic acid; alkyl halides; benzyl halides; hydrocarbyl substituted carbonates; and hydrocarbyl epoxides in combination with an acid or mixtures thereof.

Preferred quaternising agents for use herein include dimethyl oxalate, methyl 2-nitrobenzoate, methyl salicylate and styrene oxide or propylene oxide optionally in combination with an additional acid.

When a compound is a dispersant or detergent and an AFM herein, it may count as part of the defined complement of each.

In accordance with a sixth aspect of the present invention there is provided a compound which comprises:

(1) a fatty acid residue having more than 12 carbon atoms and at least one carboxylic group; and (2) a polyamine residue having more than two nitrogen atoms; wherein the mole ratio of the carboxylic groups to nitrogen atoms used to form the compound is greater than 0.8 carboxylic groups per 1 nitrogen atom.

In accordance with a seventh aspect of the present invention there is provided a method of preparing a compound of the fifth aspect, comprising reacting

(1) a fatty acid having more than 12 carbon atoms and at least one carboxylic group and (2) a polyamine having more than two nitrogen atoms; at a mole ratio of the reactant compounds greater than 0.8 carboxylic groups per 1 nitrogen atom.

In one embodiment the fatty acid and the polyamine are mixed at a temperature of, for example, 20 to 100° C. to make a salt of the fatty acid and the polyamine.

In one embodiment a fatty acid amide is prepared by a dehydration-condensation reaction between the fatty acid and the polyamine, for example at a temperature of 20 to 200° C. under atmospheric or reduced pressure.

In accordance with an eighth aspect of the present invention there is provided a fuel composition, lubricant composition, or additive composition; each comprising a compound in accordance with the fifth aspect.

The compound is preferably present in the composition of the seventh aspect in an amount up to 10,000 ppm, preferably up to 1,000 ppm, preferably from 1 to 500 ppm, preferably 10 to 200 ppm, and preferably 15 to 100 ppm.

In accordance with a ninth aspect of the present invention there is provided an additive composition containing a solvent and a compound in accordance with the fifth aspect, the additive composition being adapted for addition into a fuel and/or lubricant, with dilution therein of said compound.

Preferred aspects of any of the sixth, seventh, eighth or ninth aspects are the features expressed above as the first, second, third, fourth or fifth aspects, including preferred features thereof.

The invention will now be further described with reference to the following examples. Reference or comparative examples, not intended to be covered by the claims defining our invention, are denoted by the prefix “C”.

EXAMPLES A. Methodologies

A1. Compounds as defined above were prepared. A2. Suitable hydrocarbons were identified for friction testing and compatability studies. A3. Compatability in hydrocarbon liquids functional as a fuel or lubricant was assessed. A4. Friction reducing properties of the friction modifier compounds prepared by methods A1 were assessed using the HFRR wear scar test and/or the TE77 sliding friction test.

In greater detail:

A1. Compound Preparations Example 1 Preparation of TOFA Diethylenetriamine Amide, Molar Ratio 3/1

Tall Oil Fatty Acid (TOFA), (20 g 0.07 mol) was dissolved in toluene (22 g) in a round bottom flask fitted with a Dean and Stark attachment. Diethylenetriamine (DETA), (2.4 g 0.023 M) was added to the flask and the reaction mixture stirred under nitrogen and refluxed at 115° C. for 5 hours The water produced in the reaction is removed by azeotropic distillation.

Further amides were prepared in a similar manner with the acids, amines and ratios used identified in Table 2 below.

Example 5 Preparation of TOFA Diethylenetriamine Salt, Molar Ratio 3/1

TOFA (20 g 0.07 mol) was dissolved in toluene (22 g) in a round bottom flask. DETA (2.4 g 0.023 M) was added to the flask and the reaction mixture stirred under nitrogen for 1 hour until the exothermic reaction subsided. The salt product was then discharged.

Further amine salts were prepared in a similar manner with the acids, amines and ratios used identified in Tables 3 and 4 below.

A2. Hydrocarbons

Typical properties for hydrocarbon A used in compatibility testing and TE77 testing are as set out below.

TABLE 1 Property Unit Method Typical Results Appearance Visual Clear and Bright Colour ASTM D1500 L0.5 Kinematic Viscosity mm²/s ASTM D445 4.23 @100° C. Kinematic Viscosity mm²/s ASTM D445 18.9 @40° C. Viscosity Index · ASTM D2270 131 Density at 15° C. g/ml ASTL D4052 0.830 Pour Point ° C. ASTM D97 −21 Flash Point ° C. ASTM D92 230 Noack Volatility % wt ASTM D5800B 11.4 Saturates % HPLC >99 Sulphur ppm ASTM D2622 3 Nitrogen ppm ASTM D4629 <1 Cold Cranking −30° C. mPa · s ASTM D5293 1310 Polycyclic aromatics % wt IP346 <0.5

The hydrocarbon used for HFRR testing was different, being a unadditised unleaded gasoline, having a Research Octane Number of 95.

A3. Compatability Testing

Compatibility with a Hydrocarbon at 5% Concentration:

The solution of friction modifier in toluene was mixed with hydrocarbon A to give a concentration of 5% wt/wt active friction modifier. The evaluation was performed at room temperature. Fully miscible mixtures were recorded as Pass (P), and immiscible/separated mixtures recorded as Did Not Pass (DNP).

Compatibility with a Hydrocarbon at 10% Concentration:

The solution of friction modifier in toluene was mixed with hydrocarbon A to give a concentration of 10% active friction modifier. The evaluation was performed at room temperature. Fully miscible mixtures were recorded as Pass (P), and immiscible/separated mixtures recorded as Did Not Pass (DNP).

A4. Friction Reducing Testing TE 77 Test:

The TE77 reciprocating sliding test was used. This employed a Cameron-Plint TE77 High Frequency Reciprocating Tribometer. The piston stroke was set at ±12.4 mm, and the frequency at 25 Hz.

The TE77 Tribometer was fitted with a section of Ford F6173038 liner and a section of the corresponding Ford F6165200 compression piston ring.

The liner sample was situated in the sample bath fixed on a heated bed to enable the temperature of the sample to be adjusted according to demand.

The sample bath was filled with 10 mls of pure hydrocarbon A.

Before each experiment the machine was run for a period of time at a reduce load (10N) to ensure the system had achieved thermal equilibrium before testing began. Once thermal equilibrium was achieved, the load was increased to 75N and run for 40 minutes to establish a baseline. The data acquisition sampling occurred every second throughout the test.

After approximately 40 minutes had passed, 0.1 mls of hydrocarbon containing 100000 ppm (10% active) additive was added to the oil, providing the test hydrocarbon with 1000 ppm of the active.

Following the addition of the additive the test continued to run for a further 50 minutes.

At 30 minutes (prior to the additive addition) the friction force was logged at 50,000 Hz.

At 75 minutes (after 35 minutes post the addition of the additive) the friction force was logged at 50,000 Hz.

From this the maximum range (minimum to maximum) was calculated for each set of data.

From this the percentage reduction with the use of the additive was determined.

From the data acquired an average for the Coefficient of Friction (μ) prior to the introduction of the additive was determined by taking the averages of the values recorded between 26 to 39 minutes. The percentage change in Coefficient of Friction (μ) was then calculated from the acquired Coefficient of Friction (μ) against the average of the Coefficient of Friction (μ) prior to the introduction of the additive.

A temperature of 125° C. and a load of 75 N was chosen to screen the compounds. The additives were ranked for performance in terms of the percentage change in Coefficient of Friction.

HFRR Test

The standard test for diesel is IP 450: “Diesel fuel—Assessment of lubricity using the high-frequency reciprocating rig (HFRR)”, measuring wear scar diameter (WSD). As mentioned above, the hydrocarbon used for the tests undertaken in the context of this invention was gasoline. The test used was similar to the IP 450 test, except the test was performed at 25° C. instead of 60° C. and used a modified sample holder which holds 6 ml of sample and has a closed lid, instead of a 2 ml sample.

B. Compounds Tested and Test Results of Same B1. Amides Per Method of Example 1 Given Above

TABLE 2 Molar Compat. Compat. TE77 Poly- Ratio with HC with HC HFRR max. % Example Acid amine Acid/Polyamine 5% 10% WSD change μ Base HC 797 μm 1 TOFA DETA 3/1 P P 268 μm 54% 2C TOFA DETA 2/1 DNP DNP 3C n-hexanoic DETA 3/1 541 μm 22% acid 4 isostearic DETA 3/1 P 389 μm 48% acid

B2. Salts Per Method of Example 5 Given Above

TABLE 3 Molar Compat. Compat. TE77 Poly- Ratio with HC with HC HFRR max. % Example Acid amine Acid/Polyamine 5% 10% WSD change μ Base HC 797 μm 5 TOFA DETA 3/1 P P 226 μm 41% 6C TOFA DETA 2/1 DNP DNP 7C n hexanoic DETA 3/1 DNP 511 μm 20% acid

A further series of amine salts were prepared. In this case, the required amount of polyamine was added to a 50% solution of TOFA in toluene and the reaction mixture stirred under nitrogen for 1 hour until the exothermic reaction subsided.

TABLE 4 Compatibility Acid Polyamine Ratio Acid/amine with HC 5%  8C TOFA EDA 2/1 DNP  9 TOFA DETA 3/1 P 10C TOFA TETA 2/1 DNP 11C TOFA TETA 3/1 DNP 12 TOFA TETA 4/1 P 13C TOFA TEPA 2/1 DNP 14C TOFA TEPA 3/1 DNP 15C TOFA TEPA 4/1 DNP 16 TOFA TEPA 5/1 P 17C n octanoic acid DETA 2/1 DNP 18C n octanoic acid DETA 3/1 DNP 19C n decanoic acid DETA 2/1 DNP 20C n decanoic acid DETA 3/1 DNP 21C n dodecanoic DETA 2/1 DNP acid 22C n dodecanoic DETA 3/1 DNP acid 23C n octanoic acid TETA 4/1 DNP 24C n octanoic acid TEPA 5/1 DNP 25C n decanoic acid TETA 4/1 DNP 26C n decanoic acid TEPA 5/1 DNP 27C n dodecanoic TETA 4/1 DNP acid 28C n dodecanoic TEPA 5/1 DNP acid EDA = ethylene diamine. DETA = diethylene triamine TETA = triethylene tetramine. TEPA = tetraethylene pentamine

Example 29

A second sample of the amide used in Example 4 was prepared as follows:

Preparation of Isostearic Acid Diethylenetriamine Amide, Molar Ratio 3/1

Isostearic acid (sourced from Croda with trade name Priosine 3501) (4115 g, 13.95 mol) was dissolved in toluene (4343 g) in an oil jacketed reaction vessel fitted with an overhead stirrer and a Dean and Stark attachment. DETA (479 g, 4.65 mol) was added to the reactor over a 10 minute period and at such a rate that the temperature in the flask was maintained below 30° C. The reaction mixture was stirred under nitrogen and refluxed at 117° C. for 5 hours. Water produced in the reaction was removed by azeotropic distillation.

Example 30

The amide of Example 29 was added to a CEC RF02 reference fuel at a treat rate of 150 mg/litre active. The RF02 reference fuel characteristics are given in Table 5

TABLE 5 Specification and Properties of RF02 Basefuel Specification limits Test Description Min Max Results Units Method Density at 15° C. 0.740 0.754 0.7490 g/mL ASTM D4052 Distillation ASTM D86 I.B.Pt. 33.3 ° C. Evaporated at 70° C. 24 40 31.4 % Evaporated at 100° C. 50 58 52.5 % Evaporated at 150° C. 83 89 84.5 % F.B.Pt. 190 210 208.7 ° C. Residue 2 0.9 % vol R.O.N. 95 96.4 Units ASTM D2699 M.O.N. 85 87.1 Units ASTM D2700 Aromatics 29 35 29.6 % vol ASTM D1319 Olefins 10 0.7 % vol ASTM D1319 Saturates 69.7 % vol ASTM D1319 Reid Vapour Pressure 56 60 56.3 kPa ASTM D323 Benzene 1 <0.1 % v/v EN 238 Oxidation Stability 480 >480 minutes ASTM D525 Gum, - washed 4 <1 mg/100 mL ASTM D381 Copper Corrosion, 3 hrs at 1B ASTM D130 50° C. Lead 5 <2.5 mg/L EN 237 Phosphorous 1.3 <0.2 mg/L ASTM D3231 Sulphur 10 2.8 mg/kg ASTM D5453 Oxygen Content 1 0.77 % mass IP 466

Example 31 Vehicle Testing Procedure

Testing was undertaken using a 2008 Year 1.6 litre Proton GEN-2 Persona car.

The vehicle was fitted to a standard emission/fuel economy measurement system incorporating:

-   -   48″ single roll DC electric dynamometer     -   Speed tracking cooling fan     -   Raw engine out & tailpipe real time modal analysis, CO₂ tracer,         % EGR (Exhaust Gas Recirculation) and bag

A fuel change rig was used to allow changes between basefuel and test fuel to be made without stopping the engine.

The test cycle used was as follows:

Warm Up Phase

Vehicle warm-up, 4 EUDC (Extra Urban Driving Cycles) Basefuel stabilisation 30 minutes

Testing Phase

Basefuel 7.5 minutes Basefuel + Additive of Example 29  30 minutes Basefuel 7.5 minutes Basefuel re-stabilisation  30 minutes

During the basefuel stabilisation and 45 minute testing period the vehicle was operated at 1863 rpm in 4^(th) gear giving a vehicle speed equivalent under level road conditions of 53 kph. Modal CO₂ measurements were used to measure vehicle fuel consumption.

The results are shown in Table 6 and FIG. 1.

TABLE 6 Results of Fuel Economy Testing Average CO₂ Treat Rate Measurement % Improvement Fuel Additive mg/l active g/s in Fuel Economy RF02 None 1.533 RF02 Example 29 150 1.518 0.98

The additive of Example 29 (isostearic DETA amide at 150 mg/l) gave a rapid reduction of CO2 emissions and fuel consumption of 1.0%.

It can be seen that good results were consistently achieved using compounds formed from fatty acids of the longer carbon chain lengths and polyamines having 3 or more amine groups/nitrogen atoms, at the molar ratios of carboxylic acids to polyamine reactants which provided carboxylic acid groups commensurate with amine groups. 

1. A method of reducing friction in an engine, by adding an additive compound to a fuel and/or lubricant which is employed by the engine, the additive compound comprising: (1) a fatty acid residue having more than 12 carbon atoms and at least one carboxylic group; and (2) a polyamine residue having more than two nitrogen atoms; wherein the mole ratio of the carboxylic groups to nitrogen atoms used to form the compound is greater than 0.8 carboxylic groups per 1 nitrogen atom.
 2. The method as claimed in claim 1, wherein the additive compound is a fatty acid amide or a salt of a fatty acid and a polyamine, or a mixture thereof.
 3. The method as claimed in claim 1, wherein the fatty acid is represented by the formula: R(COOH)_(n) wherein n is 1, 2, 3 or 4, and R represents a hydrocarbyl group having at least (13 minus n) carbon atoms.
 4. The method as claimed in claim 3 wherein the fatty acid is a monocarboxylic acid having from 8 to 30 carbon atoms.
 5. The method as claimed in claim 4 wherein the fatty acid is selected from tall oil fatty acid, oleic acid and isostearic acid.
 6. The method as claimed in claim 1, wherein the polyamine is an aliphatic polyamine having a hydrocarbyl group of 4 to 50 carbon atoms.
 7. The method as claimed in claim 1, wherein the additive compound is selected from the group consisting of: the reaction product of a monocarboxylic acid having more than 12 carbon atoms and at least one carboxylic group, and diethylene triamine, in a molar ratio (expressed as the reactant compounds) of at least 2.5 to 1; the reaction product of a monocarboxylic acid having more than 12 carbon atoms and at least one carboxylic group, and triethylene tetramine, in a molar ratio (expressed as the reactant compounds) of at least 3.5 to 1; and the reaction product of a monocarboxylic acid having more than 12 carbon atoms and at least one carboxylic group, and tetraethylene pentamine, in a molar ratio (expressed as the reactant compounds) of at least 4.5 to
 1. 8-11. (canceled)
 12. A compound which comprises: (1) a fatty acid residue having more than 12 carbon atoms and at least one carboxylic group; and (2) a polyamine residue having more than two nitrogen atoms; wherein the mole ratio of the carboxylic groups to nitrogen atoms used to form the compound is greater than 0.8 carboxylic groups per 1 nitrogen atom.
 13. A method of preparing a compound as claimed in claim 12, comprising reacting: (1) a fatty acid having more than 12 carbon atoms and at least one carboxylic group, and (2) a polyamine having more than two nitrogen atoms; at a mole ratio of greater than 0.8 carboxylic groups per 1 nitrogen atom.
 14. A fuel composition comprising a fuel and a compound as claimed in claim
 12. 15. An additive composition containing a solvent and a compound as claimed in claim 12, the additive composition being adapted for addition into a fuel, with dilution therein of said compound.
 16. A method of increasing the efficiency of an engine utilising a fuel and/or lubricant, by adding an additive compound to the fuel and/or lubricant which is employed by the engine, the additive compound comprising: (1) a fatty acid residue having more than 12 carbon atoms and at least one carboxylic group; and (2) a polyamine residue having more than two nitrogen atoms; wherein the mole ratio of the carboxylic groups to nitrogen atoms used to form the compound is greater than 0.8 carboxylic groups per 1 nitrogen atom.
 17. A method of improving the friction performance of an engine lubricant, by adding an additive compound to the lubricant which is employed by the engine, the additive compound comprising: (1) a fatty acid residue having more than 12 carbon atoms and at least one carboxylic group; and (2) a polyamine residue having more than two nitrogen atoms; wherein the mole ratio of the carboxylic groups to nitrogen atoms used to form the compound is greater than 0.8 carboxylic groups per 1 nitrogen atom.
 18. The method as claimed in claim 6, wherein the aliphatic polyamine has a hydrocarbyl group of 4 to 20 carbon atoms.
 19. The method as claimed in claim 7, wherein the monocarboxylic acid is TOFA. 